1. Field of the Invention
The present invention relates to a semiconductor memory device.
2. Related Art
Memory cards (semiconductor memory cards) each having a built-in NAND-type flash memory and the like have been rapidly miniaturized and increased in capacity. To fabricate a miniaturized memory card, semiconductor elements such as a memory element and a controller element are mounted on a wiring board in a multi-layered fashion. Furthermore, to increase the capacity of the memory card, memory elements themselves are also multi-layered on the wiring board. By wire bonding, electrode pads of the semiconductor elements such as a memory element and a controller element are electrically connected to connection pads of the wiring board.
The number of layers of the memory elements has been on the increase. One possible technique has been proposed to bond wires to multi-layered semiconductor elements (memory elements) in a one-side pad structure, for example, in which the electrode pads are arranged at an end of one of the short sides of each of the semiconductor elements (e.g., refer to U.S. Pat. No. 7,061,105). In this technique, the multiple semiconductor elements are layered stepwise to expose the electrode pads. The exposed electrode pads are electrically connected to connection pads of a wiring board via bonding wires (metallic wires or the like).